1. Field of the Invention
The invention relates to a continuous process for the preparation of a reactive polymer which has chemically unbound mono- and/or bisoxazoline. This reactive polymer is in turn useful for the reactive compatibilization of polymers.
2. Discussion of the Background
The reaction of bifunctional oxazolines with polyesters or polyamides is adequately described in the literature. The terminal carboxyl groups of the particular polymer react with the oxazoline with ring opening. A reactive compatibilization polyamide 6 and polybutylene terephthalate is described in Polymer Degradation and Stability, Volume 90, 2005, 224-233. One aim of this reactive compatibilization is to combine the high impact strength of the polyamide with the chemical and water resistance of polybutylene terephthalate in one polymer blend. Reactive compatibilization of polyamide and polybutylene terephthalate with addition of 0.2-0.4% by weight of 1,3-phenylenebisoxazoline in a co-rotating double-screw extruder produces polymer blends which have improved impact strength and reduced water absorption—compared with a polymer blend which has been compatibilized without the addition of 1,3-phenylenebisoxazoline.
Journal of Applied Polymer Science, 32, (1986) 5193-5202 describes a chain extension of polyesters using oxazolines.
A continuous and exact metering of mono- and/or bisoxazoline via a funnel—as are mounted on standard commercial kneaders and extruders—is extremely difficult since these mono- and/or bisoxazolines adhere to the walls of the funnel and to the walls of the feeds. This adhesion of mono- or bisoxazoline hinders the continuous and exact metering of these compounds to polymers in standard commercial kneaders and extruders to a considerable degree.